The present invention relates to incendiary devices which are designed to ignite combustible material and are dispersed by means of an explosive charge. Such devices have both military use in the destruction of property and war materiel and civilian application, for example, in starting backfires for forest fire control. Several types of incendiary devices of the general type contemplated by the present invention have been used in the past. One common type has used a flowing, pelleted powder mixture of metal and oxidizer which is dispersed upon detonation of an explosive charge. Such devices, of course, inherently have an obvious hazard insofar as handling is concerned because the materials are spontaneously reactable. Further, they are not totally satisfactory because the pellets tend to disintegrate and burn too rapidly or detonate with the high explosive. The explosive charge tends to disperse the powders in an erratic manner, and over a very short range before burn-out occurs. Thus, neither uniformity nor extent of distribution is often optimum.
Another type of known device makes use of fragments of solid compositions such as zirconium-misch metal, or Thermits. These materials can be cast into a proper form such as the lining of a shell casing which is then filled with the explosive charge. They tend to suffer, however, from handling difficulties due to vacuums and pressures needed for fabrication and to early burn-out and failure to ignite ambient combustible material. Further these materials are brittle and tend to disintegrate upon exposure to the high explosive detonation resulting in a quick burning powder. Misch metal and zirconium also require oxygen for burning and are useless under water or other liquids or at high altitudes where oxygen is scarce.
In my copending U.S. Pat. application Ser. No. 487,474, filed concurrently herewith and entitled "Incendiary Composition" I have disclosed a composition which is made up of magnesium powder and a metal oxide or polytetrafluoroethylene oxidizer in a polysiloxane elastomer matrix. That application is incorporated herein by reference.